Forecasting is useful in several contexts. In an example context, balancing energy demand and energy supply ensures stable electricity grids. This task relies on computing accurate forecasts of future electricity consumption and production at any point in time and at any level of granularity. The increasing usage of renewable energy sources and the increasing accessibility to energy markets provide additional challenges to balancing energy demand and energy supply. Renewable energy sources are highly dependent on external influences (e.g., weather conditions), and customer energy needs can be erratic. Thus, in order to supply adequate amounts of energy to its customers, utility companies need to be capable of accurately and efficiently forecasting energy demands in real time. Historic electricity time series can provide useful starting points for optimizing current electricity forecast models.